Engine Speed (Hardwired and Bussed Input)

The TCM used both direct engine speed input from the powertrain control module (EATX RPM SIGNAL) as well as calculated engine speed input from the PCM over the PCI Bus. The direct input is required to provide immediate information for use by the TCM control logic. The PCI engine speed data is used by the TCM fail-safe logic to confirm that the direct engine speed data is valid.